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 Silvertone 3004 need help!!!!

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frank1956

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Join date : 2014-08-17

PostSubject: Silvertone 3004 need help!!!!   2014-08-17, 4:21 pm

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Hi all,
My name is Frank and I am new to this forum. I have a Silvertone 3004 that I recently acquired, all the capacitors, resistors and electrolytic capacitors have been replaced and checked. Once this was done all I got from the speaker was static, would not pick up any radio stations. The radio from the previous owner had been tinker with and had to be re-wired in some areas and cap & resistors moved around in other places. All this has been correct and is wired and has all cap's and resistors installed correctly, but still no stations just static.

It was suggested that I acquire a signal generator. I have since purchased an Eico 324 signal generator and am in the process of learning how to use it correctly. Here is is a pic of it and what came with it. I have download the instruction manual, but it is greek to me as I am brand new to this field of radio repairs. Not sure which side of the signal generator I need to use or what each control knob does? i.e. AF Mod/Output/RF Coarse etc. Any and all help would be sincerely appreciated.. Thanks in advance.

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35Z5



Join date : 2014-08-23

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 7:07 am

Well I doubt the rectifier is at issue and for the 12AV6 & 50C5 the screwdriver test on the volume control would eliminate those...

Frank here's a article on building a dim bulb tester, though all one really needs is a extension cord with bulb & switch in the hot lead(small blade on plug)... With a 40w bulb the radio may not receive enough voltage to play but on a 60w a radio with good components should play...

antiqueradio.org/dimbulb.htm
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MEZLAW

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Join date : 2012-10-28

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 8:09 am

I'm only an hour and a half from Frank. If it's any help we can meet and I can provide what he needs. Frank and I have already talked about getting together as I have some extra equipment for a modest price. Such as several old analog meters to choose from and a couple of variacs.   It all depends on whether or not he just ants to repair this one radio or he now has the bug!  Very Happy
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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 11:18 am

MEZLAW,
Me think I have the bug!!! We can get together, this is the test equipment that I have thus far.

(1) Analog meter
(2) Digital meter
(3) Eico 324 signal generator
(4) TC 142 Might Mite tube checker
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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 11:30 am

wildcat445 wrote:
Cliff, that will really help.  Thank you!

Tom, do you or Cliff either one think that there is a possibility that there is a tube with a thermal expansion issue?  Frank states that when the radio fades, the tubes stay lit.  Could we have an element in one of the tubes that is getting hot, expanding so that it kills the signal?  I'm getting a set of tubes ready to go, just in case.  I am trying them out in a radio to make sure they do not have issues.  I like subbing tubes in cases like this.

WC


Just sitting here thinking (could be dangerous) If the radio has been over night all tubes have cooled down. If I plug it in, then the thermal expansion issue should not come into play at the moment correct? In theory the radio should play or at least try to pick up a local station to the point that thermal expansion occurs thus killing the signal. This radio does not even get a station when it has set over night and tube or cold. Just an observation and question.

Frank
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wildcat445

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Join date : 2014-08-16

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 11:59 am

Yes, Frank, after the tubes have cooled, thermal expansion will not be an issue.  I'm not sure how to advise you.  

I'm wondering now if we don't just plain have a bad tube somewhere.  This radio was playing.  Then it started acting up.  That usually points to tubes.  Those are the only things you have not replaced, 12AV6 excepted, if I remember correctly.  You are getting background noise, but no station.  Correct? If you radiate a signal from your generator, can you hear it in the speaker now?

WC
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MEZLAW

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Join date : 2012-10-28

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 12:23 pm

frank1956 wrote:
MEZLAW,
Me think I have the bug!!! We can get together, this is the test equipment that I have thus far.

(1) Analog meter
(2) Digital meter
(3) Eico 324 signal generator
(4) TC 142 Might Mite tube checker


Well you will need one of my Variable Voltage Controls, commonly referred to as a Variac (trade name)   I have a few Micronta 5 amp units with should be enough for the radios you will be working on.  I have been collecting Micronta (Radio Shack) items for some time and have several vintage analog meters.  
Mictronta Range Doubler @ 50K/25K ohms/volt  22-204B
Micronta  model 22-201U @ 20K ohms/volt
Micronta flip top 22-211  @ 20K ohms/volt
Micronta model 220212  @ 2K ohms/volt

I have several of each, from needs repair to NOS.    I'll have to check and see what else I have 3 or more of.  I may have up to 4 audio generators. Usually these items kill you in price from Ebay because of the shipping costs and you can't "try before you buy."  I have two complete shops and everything else is just to much to keep.  Soon I hope to be down to one house so I will have one whole spare shop!
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MEZLAW

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 12:26 pm

What about a soldering gun? I may have 4 or 5 excellent vintage Weller 8200n units.
I prefer the way the vintage units hold the tip.
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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:15 pm

wildcat445 wrote:
Yes, Frank, after the tubes have cooled, thermal expansion will not be an issue.  I'm not sure how to advise you.  

I'm wondering now if we don't just plain have a bad tube somewhere.  This radio was playing.  Then it started acting up.  That usually points to tubes.  Those are the only things you have not replaced, 12AV6 excepted, if I remember correctly.  You are getting background noise, but no station.  Correct?  If you radiate a signal from your generator, can you hear it in the speaker now?

WC

WC, Correct background noise, but no station. When station does come it a lot of static, then BAM a radio station. If I have music/talking on the radio I can generate a signal from the signal generator and hear it through the speaker on the radio. No station no signal generated through the speaker.

Frank
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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:17 pm

MEZLAW wrote:



Well you will need one of my Variable Voltage Controls, commonly referred to as a Variac (trade name)   I have a few Micronta 5 amp units with should be enough for the radios you will be working on.  I have been collecting Micronta (Radio Shack) items for some time and have several vintage analog meters.  
Mictronta Range Doubler @ 50K/25K ohms/volt  22-204B
Micronta  model 22-201U @ 20K ohms/volt
Micronta flip top 22-211  @ 20K ohms/volt
Micronta model 220212  @ 2K ohms/volt

I have several of each, from needs repair to NOS.    I'll have to check and see what else I have 3 or more of.  I may have up to 4 audio generators. Usually these items kill you in price from Ebay because of the shipping costs and you can't "try before you buy."  I have two complete shops and everything else is just to much to keep.  Soon I hope to be down to one house so I will have one whole spare shop!


MEZLAW,
I have a brand new solder iron, but no Variac.

Frank
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:19 pm

Radio has been on for about 15 min's with no station just static  Sad 
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MEZLAW

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:31 pm

Looks like the Variac is all you will need. I only have one here and 3 at my other location. I plan to stop by there tomorrow and hopefully I'll remember to pick one up.

If anyone can think of anything else please post it.  Very Happy 
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35Z5



Join date : 2014-08-23

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:47 pm

Well I hate to say this but weak to no reception plus static noise generally points to bad IF can(s), AKA silver mica disease...
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 3:58 pm

Tom,
That does not sound good!!!! Is there a cure???


Frank
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MEZLAW

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 4:57 pm

There is a whole thread on the other board which is a step by step process to rebuilding an IF can. I doubt you'll find a replacement. Either way it will bring you past the novice level!
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Cliff Jones
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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 8:38 pm

Wait a minute!
Have you checked your tuning capacitor plates? Its a possibility you have stator and rotor plates that are touching. Check that and make sure nowhere do the movable rotating plates touch the fixed plates. Just an Idea that I don't remember seeing in the discussion.

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MEZLAW

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-24, 8:44 pm

Very good point Cliff!  Wink 
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 6:39 am

Cliff Jones wrote:
Wait a minute!
Have you checked your tuning capacitor plates? Its a possibility you have stator and rotor plates that are touching. Check that and make sure nowhere do the movable rotating plates touch the fixed plates. Just an Idea that I don't remember seeing in the discussion.

While attempting to check the tuning capacitor to insure nothing was touching, this is what happen Mad  Not sure if this is fixable or what, what a stupid mistake!!!!!

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35Z5



Join date : 2014-08-23

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 10:29 am

As long as lower edge of that plate isn't shorting that would only cause a issue at the low end of the dial, freq above probably 700 won't be affected...

In all my years I've never seen a tuning cap short that didn't cause noise when being moved through the stations... In my view without noise mentioned, thinking the cap is shorting after a few minutes of play is a stretch...

Ground pin one on the 12BA6 and see if the noise continues, if it does the 2nd IF is suspect... Also you can connect the sig generator to pin five and tune the generator to approx 455Kc, if the tone has noise the 2nd IF is probably bad... If there is no noise and a normal tone, then connect generator pin five of 12BE6, at this point any noise on the tone would indicate a bad 1st IF(but only if 1st test is clean)... For second test short out antenna with a jumper wire across it to kill reception it may have...
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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 1:23 pm

Tom,
As soon as I can get a station to come in I will preform the test. It is hit and miss when trying to get a station to come in. I can not even get the signal generate to generate a signal just with the RF cable laying next to the radio when no station are being picked up

Frank
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35Z5



Join date : 2014-08-23

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 2:50 pm

The whole idea is connect the generator when it isn't operating to find the stage that's failed...
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 4:52 pm

Tom,
Understand that, but have tried this before you suggested it. It will not pick up the signal, generated from the Eico 324 unless there is a station coming it, Don't ask me why, but that is a fact.

Frank
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35Z5



Join date : 2014-08-23

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 5:56 pm

Then you need to be checking back at the audio stages for loss of signal amplification, verifying it passes signal when operating tells you nothing...
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-25, 8:40 pm

35Z5 wrote:
As long as lower edge of that plate isn't shorting that would only cause a issue at the low end of the dial, freq above probably 700 won't be affected...

In all my years I've never seen a tuning cap short that didn't cause noise when being moved through the stations... In my view without noise mentioned, thinking the cap is shorting after a few minutes of play is a stretch...

Ground pin one on the 12BA6 and see if the noise continues, if it does the 2nd IF is suspect... Also you can connect the sig generator to pin five and tune the generator to approx 455Kc, if the tone has noise the 2nd IF is probably bad... If there is no noise and a normal tone, then connect generator pin five of 12BE6, at this point any noise on the tone would indicate a bad 1st IF(but only if 1st test is clean)... For second test short out antenna with a jumper wire across it to kill reception it may have...


Tom,
I am doing the test as I type this. Sig Gen on (455Kc) connected to pin 5 12BA6, no tone just white static. Once disconnect radio plays in and out from time to time.
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frank1956

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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-30, 8:37 pm

Tom,
I connected the hot lead of the signal generator in series with a .01 @630 volt capacitor to the terminal on the tuning cap where the antenna is connected, ground to chassis. The signal generator was warmed up for 30 min, radio was warmed up for 10 min. Radio dial was set at the low end of the radio dial and signal generator was set to 455khz and attenuation was set high enough to hear the tone, the signal sel was set to Int Mod AF Out. When the signal was injected into the antenna section of the tuning cap a tone was hear I rotated the tuning cap clockwise. The tone was loud and in some case just audible, but was never lost or cut out during the process.

Frank
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Cliff Jones
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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-31, 2:09 pm

Good!
If its loud then as you move the tuning cap, then becomes weaker, its because the generator is putting out a specific frequency, just like a station. What frequency do you have the generator set to?
PS I am at a Hospital as my Dad has Pneumonia and can't swallow so I am just trying to fill in some time on my forum, I am not trying to dominate just want do something constructive.

You have been getting good help and I am very pleased at the methodology.

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frank1956

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Join date : 2014-08-17

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-31, 3:37 pm

Cliff,
Hope all is well with your father. The Sig gen was set to 455khz.

Frank
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Cliff Jones
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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-31, 4:05 pm

Ups and downs with my Dad of 95.
I don't have references that I usually refer to.
But you would need to use that frequency if that is the correct IF Freq.
You will use that to align the IF cans. One method is putting a meter, preferably an analog , and to be hooked up to the speaker leads. As you make adjustments it will allow you to see signal amplification in the radio for peaking as it comes into alignment.

The first step is to start at the antenna then the mixer, followed by 1st. IF then 2nd IF then detector/audio.

The IFs actually act as filters to separate the mixed RF and oscillator signals. The RF is amplified and mixed with the oscillator frequency, the reason is to get a stronger signal that can be adjusted to bandwidth and to keep the signal from getting too weak or too strong. So you won't be blasted with a loud volume one second and weak volume the next. This is called AVC or Automatic volume control. These things are all designed just to make the radio easier to listen to.

So doing an alignment is critical to enjoying the radio at its best.
I am going to stop rambling now as its time to have something to eat. If you can avoid Hospital Food You are wise. No

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wildcat445

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Join date : 2014-08-16

PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-31, 7:01 pm

Thanks, Cliff. I have suggested that Frank align his set one IF at a time, rather than both at once, as is normal practice. I also suggested that he start with the second IF, closest to the speaker to prevent confusion if he had trouble getting a signal thru. When the second IF is peaked, he can go to the first one. Then do them both at the same time like the instructions dictate. I was hoping this would prove easier as it is his first time, and his radio may be really messed up alignment-wise. Oscillator tracking may prove more of a challenge.

WC

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FrankB
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PostSubject: Re: Silvertone 3004 need help!!!!   2014-08-31, 7:54 pm

Please remember a variable transformer,aka Variac (tm) is NOT an isolation transformer.

If one is too expensive , go to Radio Shack and get a matched pair of either 6, 12, or 24 V transformers, ( Actually, almost any matched pair of transformers will work, or one with a split ( pair of isolated primary windings) primary for 110 or 220 v input) of at least 2 amps and connect the secondaries together in phase.
You test the output and should get 120 V out for 120V in.
You just made an el cheepo and safe isolation tx. Do not attach any taps on the LV secondaries to anything.
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